It is often desirable for a client device (e.g., a cell phone) to support one or more types of “hands-free” operations. For example, when the user of such a client device is driving a car, it can be dangerous (and, in some jurisdictions, illegal) for the user to operate certain aspects of the client device's user interface. Particularly, entering sequences of keypresses, or other types of input entry, can be distracting to a driver. Consequently, some client devices use audio commands as replacements for manual input.